1. Field of the Invention
The present invention relates to a microwave oven, and more particularly, to a method and apparatus for compensating cooking time of a microwave oven.
2. Description of the Related Art
A related art apparatus for compensating cooking time of a microwave oven will be described with reference to FIG. 1.
As shown in FIG. 1, the related art apparatus for compensating cooking time of a microwave oven includes an input power part 1, a voltage dividing resistor 2, a regulated power circuit part 3, a data input part 6, a controller 4, a load driver 7, and a display part 5. The input power part 1 converts commercial power to a predetermined operation voltage. The voltage dividing resistor 2 divides the operation voltage from the input power part 1. The regulated power circuit part 3 uniformly maintains the operation voltage. A user selects a desired mode through the data input part 6. The controller 4 controls cooking time in accordance with the mode selected by the data input part 6. That is to say, the controller 4 receives the divided voltage from the voltage dividing resistor 2 to sense its voltage level and compensate cooking time, and outputs a corresponding control signal. The load driver 7 drives a load in accordance with the control signal. The display part 5 displays the operation state in accordance with the mode selected by the data input part 6.
The operation of the related art apparatus for compensating cooking time of a microwave oven will be described.
The input power part 1 converts the commercial power to a predetermined operation voltage, i.e., low voltage. The voltage dividing resistor 2 includes a plurality of resistors R1 and R2 connected in parallel at both ports of the input power part 1 to divide the operation voltage. The regulated power circuit part 3 uniformly maintains the operation voltage to be applied as the driving power of the controller 4.
If a user selects a menu through the data input part 6, the controller 4 controls the load driver 7 in accordance with the selected menu to proceed with a cooking mode. At this time, the controller 4 receives the voltage divided by the resistors R1 and R2 through an A/D port to sense its level. Then, the controller 4 compares the sensed voltage level with a given reference voltage to compensate cooking time. The reference voltage means a voltage of which certain value is equally applied to microwave ovens without considering voltage variation at an output port of the input power part and deviation of the resistors.
However, the aforementioned related art apparatus for compensating cooking time of a microwave oven has several problems.
First, it is difficult to exactly determine actual voltage variation of input voltage variation due to voltage variation at the output port of the input power part and deviation of the resistors.
Despite errors occurred in the A/D port due to deviation of the resistors, the voltage of the A/D port is compared with the reference voltage commonly given to the products. This makes exact data difficult to sense.
Finally, cooking time is compensated by erroneously calculating due to errors generated by deviation of the resistors, thereby reducing cooking reliability.